JP5783331B2 - Secondary battery current collection structure and secondary battery - Google Patents

Description

  The present invention relates to a current collecting structure for a secondary battery and a secondary battery.

  Nonaqueous electrolyte secondary batteries such as lithium ion batteries have the advantages of high energy density, low self-discharge and good cycle performance. Therefore, in recent years, non-aqueous electrolyte secondary batteries are expected to be used as power sources for various industrial machinery by increasing the size or capacity. In order to increase the capacity of the non-aqueous electrolyte secondary battery, it is necessary to increase the number of electrode plates accommodated in the non-aqueous electrolyte secondary battery.

  Since each electrode plate needs to be electrically connected to the electrode terminal, in a non-aqueous electrolyte secondary battery with an increased number of electrode plates to be accommodated, if each electrode plate is connected to the electrode terminal, the electrode plate In order to secure a region for connecting the electrode terminals, the electrode terminal connection portion must be enlarged. In addition, a space for connecting many electrode plates is required around the connection portion of the electrode terminal. Furthermore, when the number of electrode plates increases, there is a problem that the resistance value of the connection portion between the tabs of the electrode plates and the electrode terminals increases. In order to solve such a problem, Japanese Patent No. 4494731 (Patent Document 1) makes a plurality of products in which tabs of a plurality of electrode plates are welded to L-shaped current collecting leads (current collecting plates). A secondary battery in which tabs of a plurality of current collecting leads are welded to each other in parallel with a predetermined interval, and a plurality of current collecting lead bases are stacked and fixed to a connection portion of an electrode terminal by bolts and welding. It is disclosed.

Japanese Patent No. 4494731

  Recently, some secondary batteries have a maximum discharge current of 100A. In such secondary batteries, several hundreds of electrode plates may be stacked to form a group of electrode plates, and the tabs of the electrode plates are connected. The number of current collector plates to be used is inevitably increased. When the number of current collecting plates to be stacked increases, the electrode plate group has a larger dimension in the stacking direction of the electrode plates. For this reason, the distance between the electrode plate located near the terminal body and the electrode plate located away from the terminal body is greatly different.

  In a conventional secondary battery, in order to electrically connect a plurality of electrode plate tabs having different distances from the terminal main body to each terminal, for example, as shown in Patent Document 1, a portion where a tab of a current collector plate is welded In the structure in which the current collectors are arranged in parallel, when the number of current collector plates increases, there is a problem that a space for arranging a plurality of current collector plates increases, and the secondary battery must be enlarged.

  An object of the present invention is to provide a current collecting structure for a secondary battery that does not unnecessarily increase the installation space for the current collecting plate even if the number of electrode plates stacked in order to increase the capacity of the secondary battery is increased. It is to provide a secondary battery.

  Another object of the present invention is to provide a secondary battery that can use an electrode plate having the same tab shape even when the number of electrode plates stacked to increase the capacity of the secondary battery is increased. is there.

  An object of the present invention is to improve a current collecting structure for a secondary battery including an electrode plate group in which a plurality of electrode plates having tabs are stacked via a separator. The current collecting structure of the present invention includes a plurality of current collecting plates and terminals. Tabs of a plurality of electrode plates having the same polarity are welded to the plurality of current collector plates. The terminal has a terminal main body portion and a terminal portion to which a plurality of current collecting plates divided into two groups are attached. A plurality of current collector plates used in the present invention are to be welded in a state in which a fixed portion constituting a current collector plate laminated portion that is laminated and fixed to a terminal body portion and a plurality of tabs are overlapped. Department. The plurality of current collector plates are each formed by being bent so as to have a bent portion having a predetermined angle between the fixed portion and the welded portion. The plurality of current collector plates belonging to one group are further divided into a first small group located near the terminal body and a second small group located away from the terminal body. The plurality of current collector plates belonging to the first small group have a predetermined angle formed on one current collector plate located near the terminal main body portion of the two adjacent current collector plates. The predetermined angles of the plurality of current collecting plates are respectively determined so as to be smaller than a predetermined angle formed on the other current collecting plate located farther from the portion. The plurality of current collector plates belonging to the second small group have a predetermined angle formed on one current collector plate at a position close to the terminal main body portion of the two adjacent current collector plates. The predetermined angles of the plurality of current collector plates are respectively determined so as to be larger than the predetermined angle formed on the other current collector plate located farther from the portion.

  In the current collecting structure of the present invention, the welded portion of each current collecting plate is configured to extend radially from the end of the current collecting plate laminate on the electrode plate group side. As a result, even if the number of current collecting plates increases, a necessary number of current collecting plates can be arranged in a limited space by appropriately setting a predetermined angle. Therefore, according to the present invention, even if the number of current collecting plates increases, it is not necessary to increase the space for arranging a plurality of current collecting plates. The lengths of the welded portions of the plurality of current collector plates may all be the same, or some or all of them may be different. Also, the predetermined angles between two adjacent current collector plates may all be the same, or some or all may be different. Note that the current collecting structure of the plurality of current collecting plates belonging to the other group can be arbitrarily configured.

  The tabs of the plurality of electrode plates welded to the welded portion of the current collector plate may be routed in any way, but are preferably routed so as not to contact the tabs welded to other current collector plates. .

  In addition, this invention can also be set as the current collection structure which fixes one current collection board laminated part to a terminal part main body. In this case, the current collecting structure is configured to have one first small group and one second small group without dividing the plurality of current collecting plates into two groups.

  The predetermined angle of the current collector plate closest to the terminal body portion among the plurality of current collector plates belonging to the first small group is an acute angle, and the plurality of current collector plates belonging to the second small group Among these, it is preferable that the predetermined angle of the current collector plate located farthest from the terminal body is an acute angle. When configured in this way, the space adjacent to the terminal body can be used as a space for routing the tab, so that the predetermined angle of the current collector plate located farthest from the terminal body is obtuse It is possible to increase the number of current collector plates.

  The current collecting structure of the present invention is configured so that a plurality of current collecting plates are divided into two groups, and a plurality of current collecting plates belonging to one group are not divided into first and second small groups. Also good. In this case, for example, a plurality of sheets belonging to one group such that a plurality of welded parts are located in a region facing a surface opposite to the surface on which the terminal portion of the terminal main body portion is located. The current collector plate is arranged. Then, one of the two current collector plates adjacent to the terminal main body portion has a predetermined angle formed on one current collector plate that is farther than the terminal main body portion. The predetermined angles of the plurality of current collector plates are respectively determined so as to be smaller than the predetermined angle formed on the electric plate. If comprised in this way, the several to-be-welded part can be arrange | positioned in the area | region between a terminal part main body and an electrode group. Therefore, it is possible to easily weld the welded portion of the electrode plate in the region facing the surface located on the side opposite to the surface on which the terminal portion of the terminal main body portion is located. Further, the plurality of current collector plates are not grouped at all, and the plurality of welded portions are positioned in a region facing the surface located on the opposite side to the surface on which the terminal portion of the terminal main body portion is located. In addition, a plurality of current collector plates may be arranged.

  When a plurality of current collector plates are arranged so that a plurality of welded parts are located in a region facing a surface opposite to the surface on which the terminal portion of the terminal main body is located, Of the current collector plates, it is preferable that the predetermined angle of the current collector plate closest to the terminal body is an acute angle.

  The plurality of current collector plates may be arranged such that the plurality of welded portions are positioned outside a region facing a surface located on the opposite side to the surface on which the terminal portion of the terminal main body portion is positioned. In this case, a predetermined angle formed on one current collector plate located near the terminal main body portion between two adjacent current collector plates is another one farther than the terminal main body portion. The predetermined angles of the plurality of current collector plates are respectively determined so as to be larger than the predetermined angle formed on the current collector plates. If comprised in this way, the several to-be-welded part can arrange | position several to-be-welded parts on the outer side of the area | region between a terminal part main body and an electrode group. Therefore, it is possible to easily weld the welded portion of the electrode plate outside the region facing the surface opposite to the surface where the terminal portion of the terminal main body portion is located. Further, the plurality of current collector plates are not grouped at all, and the plurality of welded portions are positioned outside the region facing the surface opposite to the surface on which the terminal portion of the terminal main body portion is positioned. As such, a plurality of current collector plates may be arranged.

  When arranging a plurality of current collector plates so that the plurality of welded parts are located outside the area facing the surface located on the opposite side of the terminal part of the terminal body part, It is preferable that the predetermined angle of the current collector plate located farthest from the terminal body portion among the plurality of current collector plates is an acute angle.

  If the difference between the predetermined angles of the two adjacent current collector plates is too small, the space between the welded portions of the two adjacent current collector plates is narrowed, and a sufficient number of sheets are provided for each current collector plate. In some cases, the tab of the electrode plate cannot be welded. Also, if the difference between the predetermined angles of two adjacent current collector plates is too large, the number of electrode tabs that can be welded to each current collector plate can be increased, but a desired number of current collector plates can be connected to the terminals. The case where it cannot weld to a main-body part arises. Therefore, it is preferable that the predetermined angle difference between the two adjacent current collector plates is 5 ° to 15 °. If the predetermined angle difference is within this range, both the number of electrode tabs that can be welded to each current collector and the number of current collectors that can be welded to the terminal body can be increased. Of course, the difference in the predetermined angle may be out of the above range depending on the output or configuration of the secondary battery in which the terminal structure of the present invention is mounted.

  In the case where the plurality of current collector plates are divided into two groups, it is preferable that the current collector plates are respectively fixed to two end faces opposed to each other in the stacking direction of the electrode plate group of the terminal body portion. If comprised in this way, many electrode plates can be connected rather than the case where a collector plate lamination | stacking part is fixed only to one end surface of a terminal main-body part. In addition, a plurality of current collector plates divided into two groups can be easily connected to the terminal portion body.

  This invention can also be grasped | ascertained for nonaqueous electrolyte secondary batteries.

It is a top view of the lithium ion secondary battery as a nonaqueous electrolyte secondary battery of one Embodiment of the current collection structure of this invention. It is a front view which shows the internal structure of the lithium ion secondary battery of embodiment of FIG. It is a right view of the electrode group of embodiment of FIG. It is the figure which isolate | separated and showed the positive electrode tab of the positive electrode plate, the positive electrode current collecting plate, the positive electrode terminal, and the volt | bolt. It is a figure which shows typically the current collection structure of the positive electrode terminal of embodiment of FIG. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 2nd Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 3rd Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 4th Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 5th Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 6th Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 7th Embodiment of this invention. It is a figure which shows typically the current collection structure of the positive electrode terminal of the 8th Embodiment of this invention.

  Hereinafter, with reference to drawings, the current collection structure and the configuration of an embodiment of a secondary battery according to the present invention will be described in detail. FIG. 1 is a plan view of a lithium ion secondary battery 1 as a non-aqueous electrolyte secondary battery to which an embodiment of the current collecting structure of the present invention is applied, and FIG. 2 shows the inside of the lithium ion secondary battery 1. It is a front view which shows a structure. In the present embodiment, the thickness dimensions of some components are exaggerated for easy understanding.

  As shown in FIGS. 1 and 2, the lithium ion secondary battery 1 of the present embodiment includes an electrode plate group 3 and a stainless-steel prismatic battery container 5 that accommodates the electrode plate group 3 therein. Yes. The battery container 5 includes a battery can 7 having one end opened, and a battery lid 9. After the electrode plate group 3 is inserted into the battery can 7, the opening peripheral edge of the battery can 7, and the battery lid It is sealed by welding the peripheral part of 9.

  A positive electrode terminal 11 and a negative electrode terminal 13 made of aluminum are fixed to the battery lid 9. The positive electrode terminal 11 and the negative electrode terminal 13 include terminal portions 11 a and 13 a that pass through the cover plate of the battery lid 9 and protrude to the outside of the battery container 5, and terminal main body portions 11 b and 13 b disposed in the battery container, respectively. Have. An annular inner packing 15 is provided between the positive electrode terminal 11 and the negative electrode terminal 13 and the battery lid 9. An annular outer packing 17 and a terminal washer 19 are provided on the outer side of the battery lid 9 so as to be opposed to the inner packing 15 via the battery lid 9. The positive electrode terminal 11 and the negative electrode terminal 13 are respectively attached to the battery lid 9 by a positive terminal nut 21 and a negative terminal nut 23 provided at the tip of the threaded portion via the inner packing 15, the outer packing 17, and the terminal washer 19. It is fixed. The portion of the battery lid 9 where the positive electrode terminal 11 and the negative electrode terminal 13 are provided ensures a sealed / sealed state in the battery container 5 by the inner packing 15 and the outer packing 17.

The battery lid 9 is provided with a gas discharge valve 9a and a liquid injection port 9b welded with stainless steel foil. The gas discharge valve 9a has a function of cleaving the stainless steel foil and releasing the internal gas when the battery internal pressure increases. A non-aqueous electrolyte (not shown) in which lithium hexafluorophosphate (LiPF ₆ ) or lithium tetrafluoroborate (LiBF ₄ ) is dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate is injected from the liquid injection port 9b. The After injection of the electrolytic solution, the liquid injection port 9b is sealed with a liquid port stopper.

  A positive electrode side pressing member 25 and a positive electrode current collector laminated portion 27 are attached to the terminal main body portion 11 b of the positive electrode terminal 11 by bolts 29. Further, the negative electrode side pressing member 31 and the negative electrode current collector laminated portion 33 are attached to the terminal main body portion 13 b of the negative electrode terminal 13 by bolts 29.

  FIG. 3 is a right side view of the electrode plate group 3 of the present embodiment. In addition, in FIG. 3, in order to make an understanding easy, each structural member is shown typically. Therefore, each component shown in FIG. 3 is different in shape, size, and the like from the actual component of the electrode plate group. The electrode plate group 3 is configured by alternately stacking a plurality of positive electrode plates 35 and a plurality of negative electrode plates 37 via separators 39. The separator 39 prevents the positive electrode plate 35 and the negative electrode plate 37 from contacting and short-circuiting.

  The positive electrode plate 35 includes a positive electrode current collector made of an aluminum foil formed in a substantially rectangular plate shape, and a positive electrode active material layer provided on both surfaces of the positive electrode current collector. The positive electrode active material layer is prepared by mixing, for example, lithium manganese complex oxide powder, scaly graphite as a conductive material, and polyvinylidene fluoride (PVDF) as a binder at a weight ratio of 85: 10: 5. A slurry obtained by adding and kneading a dispersion solvent N-methylpyrrolidone (NMP) is applied to the positive electrode current collector, followed by drying and pressing. A positive electrode tab 35 a is integrally formed on the side of the positive electrode current collector that extends along the battery lid 9. The positive electrode tab 35a is joined to a positive electrode current collector plate described later by ultrasonic welding or laser welding. The plurality of positive plates and the plurality of positive tabs 35a are formed in the same shape.

  The negative electrode plate 37 includes a negative electrode current collector made of an electrolytic copper foil formed in a substantially rectangular plate shape, and negative electrode active material layers provided on both surfaces of the negative electrode current collector. For example, the negative electrode active material layer is prepared by adding 10 parts by mass of PVDF as a binder to 90 parts by mass of amorphous carbon powder as a negative electrode active material, and adding and kneading a dispersion solvent NMP to the slurry. It can form by apply | coating to both surfaces of a 10 micrometers electrolytic copper foil, and drying and pressing. A negative electrode tab 37 a is integrally formed on the side of the negative electrode current collector that extends along the battery lid 9. The negative electrode tab 37a is formed so as not to face the positive electrode tab 35a when the positive electrode plate 35 and the negative electrode plate 37 are laminated. The negative electrode tab 37a is joined to a negative electrode current collector plate described later by ultrasonic welding or laser welding. The plurality of negative plates and the plurality of negative tabs 37a are formed in the same shape.

  The separator 39 is formed in a substantially rectangular sheet shape by a polyethylene porous material through which lithium ions can pass. The separator 39 has a size that can prevent the positive electrode current collector of the positive electrode plate 35 and the negative electrode current collector of the negative electrode plate 37 from contacting each other in a stacked state.

  In FIG. 3, only six positive plates, six negative plates, and 12 separators are shown for ease of illustration, but the lithium ion secondary battery 1 of the present embodiment is shown. Actually, 360 positive electrode plates, 360 negative electrode plates, and 720 separators are laminated to constitute the electrode plate group 3.

  FIG. 4 is a view showing the positive electrode tab 35a, the positive electrode current collector plate 41 (a to j), the positive electrode terminal 11 and the bolt 29 separately of the positive electrode plate of the nonaqueous electrolyte secondary battery of the present embodiment. FIG. 5 is a diagram schematically showing a current collecting structure of the positive electrode terminal 11 of the lithium ion secondary battery 1 of the present embodiment. In the lithium ion secondary battery of the present embodiment, since the current collecting structure on the positive electrode side and the current collecting structure on the negative electrode side are the same, only the current collecting structure on the positive electrode side is illustrated and described. A part of the illustration and description of the current collecting structure is omitted.

  4 and 5, the separator and the negative electrode plate are not shown. Further, in FIG. 5, for ease of illustration, the positive electrode current collector plate is illustrated as having one positive electrode plate welded thereto, but actually, as illustrated in FIG. 4, Positive electrode tabs 35a of a plurality of positive electrode plates 35 are welded to the positive electrode current collector plates 41a to 41j, respectively.

  In the terminal main body 11b of the positive electrode terminal 11, two screw holes 11d to which the bolts 29 are fastened are formed in the surface 11c facing in the stacking direction. The screw holes 11d are formed near the ends on both sides in the longitudinal direction of the surface 11c. Inside the screw hole 11d, a female screw that is screwed into a screw portion provided at the tip of the bolt 29 is formed. The surface 11 c has a size that completely faces the positive electrode side pressing member 25. Between the two screw holes 11d, there is provided a protruding surface 11e that protrudes toward the positive-side holding member 25 from a portion where the screw hole 11d is provided. The protruding surface 11e protrudes toward the positive electrode side pressing member 25 from the portion where the two screw holes 11d are provided. In the terminal body portion 11b of the present embodiment, as shown in FIG. 5, the screw hole 11d and the protruding surface 11e are also formed in the surface 11f facing the surface 11c of the terminal body portion 11b in the stacking direction. Two positive current collector laminated portions 27 are respectively attached to two opposing surfaces of the portion 11b using a positive electrode side pressing member 25, a bolt 29, and a nut 13d.

  Similarly to the terminal body portion 11b of the positive electrode terminal 11, the terminal body portion 13b of the negative electrode terminal 13 has two screw holes 13d and a projecting surface to which the bolt 29 is fastened to the two surfaces 13c and 13f facing each other in the stacking direction. 13e is formed. A female screw is also formed inside the screw hole 13d. The surfaces 13 c and 13 f have a size that completely faces the negative electrode side pressing member 31.

  The positive electrode side pressing member 25 is formed in a substantially rectangular parallelepiped shape from aluminum. The positive electrode side pressing member 25 is formed with two through holes 25a through which the bolts 29 pass in the vicinity of both ends in the longitudinal direction. The positive electrode side pressing member 25 is attached to the terminal main body portion 11 b with the positive electrode current collector plate laminated portion 27 sandwiched between the positive electrode terminal 11 and the terminal main body portion 11 b.

  The negative electrode side pressing member 31 is formed in a substantially rectangular parallelepiped shape from copper. The negative electrode side pressing member 31 is formed with two through holes 31a through which the bolts 29 pass in the vicinity of both ends in the longitudinal direction. The negative electrode side pressing member 31 is attached to the terminal main body portion 13b with the negative electrode current collector laminated portion 33 sandwiched between the negative electrode terminal main body portion 13b.

  Similarly, two negative electrode current collector laminated portions 33 are attached to the terminal main body portion 13b of the negative electrode terminal 13 of the present embodiment.

  Each of the positive electrode tabs 35a is welded to the positive electrode current collector plate 41 by ultrasonic welding or laser welding 18 by ultrasonic welding. In FIG. 4, the positive electrode current collector plate to which each positive electrode tab 35a is welded is indicated by an arrow. In the present embodiment, 18 negative electrode tabs 37a are welded to the negative electrode current collecting plate 51 by ultrasonic welding or laser welding.

  In the present embodiment, as shown in FIG. 5, 20 positive current collectors 41 are divided into two groups of 10 pieces each. FIG. 4 shows only four positive electrode current collector plates 41a, 41b, 41f and 41j. The positive electrode current collector plates 41a to 41j are respectively provided with fixed portions 43 (43a to 43j) constituting the positive electrode current collector plate lamination portion 27 and welded portions 45 (45a to 45j) to which the positive electrode tabs 35a are welded. ing. In the present embodiment, the fixed portion 43 and the welded portion 45 are configured by bending a positive electrode current collector plate 41 made of aluminum formed in a substantially rectangular shape at a bent portion 47 (47a to 47j). The positive electrode current collectors 41a to 41j have the same shape before being bent. In the fixed portion 43 of the present embodiment, two through holes 49 through which the bolts 29 pass are formed in the vicinity of both end portions of the portion sandwiched between the terminal main body portion 11b of the positive electrode terminal 11 and the positive electrode side pressing member 25. ing. The positive electrode current collector laminating portion 27 is configured by sequentially laminating the welded portions 45a to 45j.

  The positive electrode current collector plate 41 a attached to a position adjacent to the positive electrode side pressing member 25 has a welded portion 45 a bent in a direction from the terminal body 11 b toward the positive electrode side pressing member 25. The positive electrode current collector plate 41a is bent so that the angle of the bent portion 47a between the fixed portion 43a and the welded portion 45a is 80 °.

  Similarly to the positive electrode current collector plate 41a, the positive electrode current collector plates 41b to 41e have a welded portion 45a bent in a direction from the terminal body 11b toward the positive electrode side pressing member 25. The angles of the bent portions 47b to 47e of the positive electrode current collector plates 41b to 41e are 90 °, 100 °, 110 °, and 120 °, respectively. The welded portions 45a to 45e of the positive electrode current collector plates 41a to 41e are located outside the region AR facing the surface S2 located on the opposite side to the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located. . In the present embodiment, the second small group of the positive electrode current collector plates is constituted by the positive electrode current collector plates 41a to 41e.

  The positive electrode current collector plates 41f to 41j are formed by bending welded portions 45f to 45j in a direction from the positive electrode side pressing member 25 toward the terminal main body portion 11b. The angles of the bent portions 47f to 47j of the positive electrode current collector plates 41f to 41j are 120 °, 110 °, 100 °, 90 °, and 80 °, respectively. Therefore, the welded portions 45f to 45j of the positive electrode current collector plates 41f to 41j are located in the region AR facing the surface S2 located on the opposite side to the surface S1 on which the terminal portion 11a of the terminal main body portion 11b is located. Yes. In the present embodiment, the first small group of the positive electrode current collector plates is constituted by the positive electrode current collector plates 41f to 41j.

  Eighteen positive electrode tabs 35a of the positive electrode plate 35 are welded to the welded portions 45a to 45j of the positive electrode current collector plates 41a to 41j in order from the end of the electrode plate group 3 in the stacking direction. In the present embodiment, a positive electrode tab 35 a of the positive electrode plate 35 having a short distance from the positive electrode current collector plate stacking portion 27 is welded to the positive electrode current collector plate on the center side of the positive electrode current collector plate stacking portion 27. For example, the positive electrode current collector plates 41e and 41f are welded with the positive electrode plate in a position overlapping with the positive electrode current collector plate lamination portion 27 when the electrode plate group 3 and the positive electrode terminal 11 are viewed from the lid member 9 side. Further, the positive electrode tabs 35 a of the positive electrode plate 35 having a long distance from the positive electrode current collector plate laminate portion 27 are welded to the positive electrode current collector plates on both ends in the stacking direction of the positive electrode current collector plate laminate portion 27. For example, the positive electrode current collector plates 41 a and 41 j are welded with the positive electrode plate in a position that does not overlap with the positive electrode current collector plate lamination portion 27 when the electrode plate group 3 and the positive electrode terminal 11 are viewed from the lid member 9 side. .

  As shown in FIG. 5, the positive electrode tab of the positive electrode plate welded to the positive electrode current collector plate 41e is farther from the positive electrode current collector plate stack portion 27 than the positive electrode tab of the positive electrode plate welded to the positive electrode current collector plate 41a. After being routed so as to largely detour in the direction, it is welded to the positive electrode current collector plate. Therefore, even if the shape of each positive electrode current collector plate and the shape of each electrode plate are the same, each positive electrode tab can be connected to the positive electrode current collector plate.

  In the present embodiment, the 20 negative electrode current collector plates 51 are divided into two groups of 10 sheets each to constitute two negative electrode current collector plate stacked portions 33. Each of the two negative electrode current collector plate stack portions 33 is composed of ten negative electrode current collector plates 51 (51a to 51j). The negative electrode current collector plates 51a to 51j each include a fixed portion 53 (53a to 53j) constituting the negative electrode current collector plate stack portion 33 and a welded portion 55 (55a to 55j) to which the negative electrode tab 37a is welded. ing. In the present embodiment, the fixed portion 53 and the welded portion 55 are configured by bending the negative electrode current collector plate 51 made of nickel formed in a substantially rectangular parallelepiped shape by the bending portion 57. In the fixed portion 53, two through holes 49 through which the bolts 29 pass are formed in the vicinity of both ends of the portion sandwiched between the terminal main body portion 13b of the negative electrode terminal 13 and the negative electrode side pressing member 31. The negative electrode current collector laminating portion 33 is configured by sequentially laminating the welded portions 55a to 55j.

  The current collecting structure on the negative electrode side also has the same structure as the positive electrode structure on the positive electrode side. Therefore, in FIGS. 4 and 5, reference numerals are attached in parentheses, reference numerals of constituent members on the negative electrode side are attached, and explanation of the current collecting structure on the negative electrode side is omitted.

  In the above embodiment, the plurality of positive electrode current collector plates and negative electrode current collector plates are divided into two groups, respectively, and the positive electrode current collector plates belonging to the respective groups are arranged on two surfaces opposed to the stacking direction of the terminal body portion, and Although the fixed part of the negative electrode current collector plate is fixed, the current collector plates may be fixed to one surface of the terminal body portion without dividing the current collector plates into two groups. Of course.

  Further, in the embodiment of FIG. 5, the current collector plate of one group is to be welded within the area AR facing the surface S2 located on the opposite side of the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located. Is divided into a first small group in which the welded portion is located outside the area AR. However, it is not necessary to divide a plurality of current collector plates belonging to one group into two small groups. FIG. 6 shows a current collecting structure according to the second embodiment of the present invention. As shown in FIG. 6, an area facing a surface S2 located on the opposite side of the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located is to be welded to a plurality of current collector plates belonging to one group. You may make it locate outside AR. Further, as in the third embodiment shown in FIG. 7, the welded portions of a plurality of current collector plates belonging to one group are placed on the side opposite to the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located. You may make it locate in the area | region AR facing the surface S2 located. Further, as in the fourth embodiment shown in FIG. 8, the welded portions of the plurality of current collector plates belonging to one group are placed on the side opposite to the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located. The portion to be welded of a plurality of current collector plates belonging to one group remaining in the area AR facing the positioned surface S2 is opposite to the surface S1 where the terminal portion 11a of the terminal main body portion 11b is positioned. You may make it locate outside the area | region AR facing surface S2 located in this.

  Furthermore, a plurality of current collector plates may be combined into one group without being divided into two groups. In the fifth embodiment shown in FIG. 9, a current collecting structure in which a plurality of non-grouped current collecting plates are welded to only one surface facing the stacking direction of the terminal body 11 b of the positive electrode terminal 11. It is shown. In FIG. 9, the plurality of current collector plates are divided into two small groups, and the welded portion of the current collector plate of one small group has a surface S1 on which the terminal portion 11a of the terminal main body portion 11b is located. Is located in the area AR facing the surface S2 located on the opposite side, and the welded part of the current collector plate of another small group is located outside the area AR. Further, as in the sixth embodiment shown in FIG. 10, the plurality of current collector plates need not be divided into two groups and two small groups. In FIG. 10, the welded portions of all the current collector plates are located in a region AR facing the surface S2 located on the opposite side to the surface S1 where the terminal portion 11a of the terminal main body portion 11b is located.

  In the embodiment shown in FIGS. 1 to 5, a plurality of current collector plates divided into two groups are divided into two small groups, but only one group is divided into small groups. Also good. In this case, for example, as in the seventh embodiment shown in FIG. 11, the surface of the terminal body 11b where the terminal portion 11a of the terminal main body portion 11b is located on the welded portion of the current collector plates that are not divided into small groups. You may make it locate outside the area | region AR which opposes the surface S2 located in the opposite side to S1. Further, as in the eighth embodiment shown in FIG. 12, the welded portions of a plurality of current collector plates that are not divided into small groups may be positioned in the area AR.

  In the said embodiment, all the angle differences of the bending part of two adjacent positive electrode current collector plates (negative electrode current collector plate) are 10 degrees. However, it goes without saying that an angle difference other than 10 ° may be used. Moreover, you may make it the angle difference of the bending part of two adjacent positive electrode current collector plates and negative electrode current collector plates differ.

  Moreover, in the said embodiment, although the length of a to-be-welded part is made the same, it is needless to say that the length of a to-be-welded part may be varied.

  Further, in each of the above embodiments, the lithium ion secondary battery has been described. However, the present invention is not limited to this, and may be applied to other secondary batteries and electrode structures thereof. is there.

  In the current collecting structure of the present invention, the welded portion of each current collector plate is configured to extend radially from the end portion on the electrode plate group side of the current collector plate stacking portion. Even if the number of the current collectors increases, a necessary number of current collecting plates can be arranged in a limited space by appropriately determining the predetermined angle. Therefore, according to the present invention, even if the number of current collecting plates increases, it is not necessary to increase the space for arranging a plurality of current collecting plates.

DESCRIPTION OF SYMBOLS 1 Lithium ion secondary battery 3 Electrode plate group 5 Battery container 7 Battery can 9 Battery cover 9a Gas discharge valve 9b Injection port 11 Positive electrode terminal 11a Terminal part 11b Terminal body part 11c surface 11d Screw hole 11e Projection surface 11f Surface 13 Negative electrode terminal 13a terminal portion 13b terminal main body portion 13c surface 13d screw hole 13e projecting surface 13f surface 15 inner packing 17 outer packing 19 terminal washer 21 positive terminal nut 23 negative terminal nut 25 positive side holding member 27 positive current collector laminated portion 29 bolt 31 Negative electrode side holding member 33 Negative electrode current collector plate laminated portion 35 Positive electrode plate 35a Positive electrode tab 37 Negative electrode plate 37a Negative electrode tab 39 Separator 41 Positive electrode current collector plate 43 Fixed portion 45 Welded portion 47 Folded portion 51 Negative electrode current collector plate 53 Fixed Part 55 Welded part 57 Folded part

Claims (16)

A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates divided into two groups are attached and a terminal having a terminal portion;
The plurality of current collector plates divided into the two groups are overlapped with a fixed portion that constitutes a current collector plate laminated portion that is laminated and fixed to the terminal body portion, and a plurality of the tabs. A welded portion to be welded in a state,
The plurality of current collector plates divided into the two groups are each formed by being bent so as to have a bent portion of a predetermined angle between the fixed portion and the welded portion,
The plurality of current collecting plates belonging to one group are divided into a first small group located near the terminal body and a second small group located away from the terminal body. ,
The plurality of current collecting plates belonging to the first small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is directed toward the terminal main body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The predetermined angles of the plurality of current collector plates are respectively determined so as to be smaller than the predetermined angle formed on the current collector plate,
The plurality of current collector plates belonging to the second small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is separated from the terminal body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The predetermined angles of the plurality of current collector plates are respectively determined so as to be larger than the predetermined angle formed on the current collector plate,
The predetermined angle of the current collector plate at a position closest to the terminal main body portion among the plurality of current collector plates belonging to the first small group is an acute angle;
The predetermined angle of the current collector plate at a position farthest from the terminal body portion among the plurality of current collector plates belonging to the second small group is an acute angle;
The difference between the predetermined angles of the two adjacent current collector plates is 5 ° to 15 °;
The plurality of current collector plates divided into the two groups are respectively fixed to two end faces of the terminal body portion facing the stacking direction of the electrode plate group. Current collecting structure. A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates divided into two groups are attached and a terminal having a terminal portion;
The plurality of current collector plates divided into the two groups are overlapped with a fixed portion that constitutes a current collector plate laminated portion that is laminated and fixed to the terminal body portion, and a plurality of the tabs. A welded portion to be welded in a state,
The plurality of current collector plates divided into the two groups are each formed by being bent so as to have a bent portion of a predetermined angle between the fixed portion and the welded portion,
The plurality of current collecting plates belonging to one group are divided into a first small group located near the terminal body and a second small group located away from the terminal body. ,
The plurality of current collecting plates belonging to the first small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is directed toward the terminal main body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The predetermined angles of the plurality of current collector plates are respectively determined so as to be smaller than the predetermined angle formed on the current collector plate,
The plurality of current collector plates belonging to the second small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is separated from the terminal body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The current collecting structure for a secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be larger than the predetermined angle formed on the current collecting plate . A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates are attached and a terminal having a terminal portion;
The plurality of current collector plates are each laminated and fixed to the terminal main body portion, and a fixed portion constituting a current collector plate lamination portion and a welded portion welded in a state where the plurality of tabs overlap. And
The plurality of current collector plates are each formed by being bent so as to have a bent portion having a predetermined angle between the fixed portion and the welded portion,
The plurality of current collector plates are divided into a first small group located near the terminal body part and a second small group located away from the terminal body part,
The plurality of current collecting plates belonging to the first small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is directed toward the terminal main body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The predetermined angles of the plurality of current collector plates are respectively determined so as to be smaller than the predetermined angle formed on the current collector plate,
The plurality of current collector plates belonging to the second small group are bent between the fixed portion and the welded portion in a direction in which the welded portion is separated from the terminal body portion, and adjacent to each other. The other one sheet in which the predetermined angle formed on one current collector plate located near the terminal main body portion is farther than the terminal main body portion among the two current collector plates that match. The current collecting structure for a secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be larger than the predetermined angle formed on the current collecting plate . The predetermined angle of the current collector plate at a position closest to the terminal main body portion among the plurality of current collector plates belonging to the first small group is an acute angle;
3. The secondary battery according to claim 2, wherein the predetermined angle of the current collector plate located farthest from the terminal body portion among the plurality of current collector plates belonging to the second small group is an acute angle. Current collecting structure. The predetermined angle of the current collector plate at a position closest to the terminal main body portion among the plurality of current collector plates belonging to the first small group is an acute angle;
4. The secondary battery according to claim 3, wherein the predetermined angle of the current collector plate located farthest from the terminal main body portion among the plurality of current collector plates belonging to the second small group is an acute angle. 5. Current collecting structure. A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates divided into two groups are attached and a terminal having a terminal portion;
The plurality of current collector plates divided into the two groups are overlapped with a fixed portion that constitutes a current collector plate laminated portion that is laminated and fixed to the terminal body portion, and a plurality of the tabs. A welded portion to be welded in a state,
The plurality of current collector plates divided into the two groups are each formed by being bent so as to have a bent portion of a predetermined angle between the fixed portion and the welded portion,
In the plurality of current collector plates belonging to one group, the plurality of welded portions are positioned in a region facing a surface of the terminal main body portion that is opposite to the surface on which the terminal portion is positioned. Are arranged to
The plurality of current collector plates belonging to the one group are bent between the fixed portion and the welded portion in a direction in which the welded portion is directed toward the terminal body portion, and adjacent to each other. Among the current collector plates, the predetermined angle formed on one current collector plate located near the terminal main body portion is another one of the other current plates located farther than the terminal main body portion. The current collecting structure for a secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be smaller than the predetermined angle formed on the current collecting plate. A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates are attached and a terminal having a terminal portion;
The plurality of current collector plates are each laminated and fixed to the terminal main body portion, and a fixed portion constituting a current collector plate lamination portion and a welded portion welded in a state where the plurality of tabs overlap. And
The plurality of current collector plates are each formed by being bent so as to have a bent portion having a predetermined angle between the fixed portion and the welded portion,
The plurality of current collector plates are arranged such that the plurality of welded portions are located in a region facing a surface of the terminal main body portion that is opposite to the surface on which the terminal portion is located. And
The plurality of current collector plates are bent between the fixed portion and the welded portion in a direction in which the welded portion is directed toward the terminal body portion, and the two current collector plates adjacent to each other. The predetermined angle formed on one current collector plate located close to the terminal main body portion is formed on another current collector plate located farther than the terminal main body portion. The current collecting structure for a secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be smaller than the predetermined angle.   The current collecting structure for a secondary battery according to claim 6, wherein the predetermined angle of the current collecting plate located closest to the terminal main body portion among the plurality of current collecting plates is an acute angle.   The current collecting structure for a secondary battery according to claim 7, wherein the predetermined angle of the current collecting plate located closest to the terminal main body portion among the plurality of current collecting plates is an acute angle. A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates divided into two groups are attached and a terminal having a terminal portion;
The plurality of current collector plates divided into the two groups are overlapped with a fixed portion that constitutes a current collector plate laminated portion that is laminated and fixed to the terminal body portion, and a plurality of the tabs. A welded portion to be welded in a state,
The plurality of current collector plates divided into the two groups are each formed by being bent so as to have a bent portion of a predetermined angle between the fixed portion and the welded portion,
The plurality of current collector plates belonging to one group include a plurality of the welded portions outside a region facing a surface of the terminal main body portion opposite to a surface on which the terminal portion is located. Arranged to be located,
The plurality of current collecting plates belonging to the one group are bent between the fixed portion and the welded portion in a direction in which the welded portion is separated from the terminal body portion, and adjacent to each other. Among the current collector plates, the predetermined angle formed on one current collector plate located near the terminal main body portion is another one of the other current plates located farther than the terminal main body portion. The current collecting structure for a secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be larger than the predetermined angle formed on the current collecting plate. A current collecting structure of a secondary battery comprising a group of electrode plates in which a plurality of electrode plates having tabs are laminated via a separator,
A plurality of current collector plates each welded with the tabs of a plurality of the same polarity plates;
A terminal body portion to which the plurality of current collector plates are attached and a terminal having a terminal portion;
The plurality of current collector plates are each laminated and fixed to the terminal main body portion, and a fixed portion constituting a current collector plate lamination portion and a welded portion welded in a state where the plurality of tabs overlap. And
The plurality of current collector plates are each formed by being bent so as to have a bent portion having a predetermined angle between the fixed portion and the welded portion,
The plurality of current collector plates are arranged such that the plurality of welded portions are located outside a region facing a surface of the terminal main body portion that is opposite to the surface on which the terminal portion is located. And
The plurality of current collector plates are bent between the fixed portion and the welded portion in a direction in which the welded portion is separated from the terminal main body portion, and the two current collector plates adjacent to each other. The predetermined angle formed on one current collector plate located close to the terminal main body portion is formed on another current collector plate located farther than the terminal main body portion. The current collecting structure of the secondary battery, wherein the predetermined angles of the plurality of current collecting plates are respectively determined so as to be larger than the predetermined angle.   11. The current collecting structure for a secondary battery according to claim 10, wherein the predetermined angle of the current collecting plate located farthest from the terminal main body portion among the plurality of current collecting plates is an acute angle.   The current collecting structure for a secondary battery according to claim 11, wherein the predetermined angle of the current collecting plate located farthest from the terminal main body portion among the plurality of current collecting plates is an acute angle.   14. The current collecting structure for a secondary battery according to claim 2, wherein a difference between the predetermined angles of the two current collecting plates adjacent to each other is 5 ° to 15 °.   The plurality of current collector plates divided into the two groups are respectively fixed to two end faces of the terminal main body portion facing each other in the stacking direction of the electrode plate group. Secondary battery current collector structure. The secondary battery provided with the current collection structure of any one of Claims 1 thru | or 13.

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